Chelsea complete signing of Zouma

Chelsea have completed the signing of St Etienne defender Kurt Zouma, with the defender loaned back to the French club for the rest of the season.

Zouma was part of the France team that won the Under-20 World Cup last year and moves for a reported fee of around £12.5 million.

A statement on the Chelsea website read: "Chelsea have today signed Zouma from St Etienne. He will remain on loan at the French club for the rest of the season. The 19-year-old central defender has joined on a five-and-a-half year contract."

Zouma has made 12 league appearances for France's fourth-placed side, St Etienne, this season and is a France Under-21 international.

He was born in Lyon and joined the club four years ago before turning professional in 2011. Zouma has made a total of 52 league appearances for St Etienne and scored four goals.

Zouma had attracted interest from many clubs across Europe this season despite being banned for 10 matches in November for a leg-breaking tackle on Sochaux midfielder Thomas Guerbert.

He hinted earlier this month that he would like to move to Chelsea, suggesting he had already spoken with Jose Mourinho.

His arrival at Chelsea will raise questions about the long-term futures of John Terry, whose contract expires this summer, and David Luiz, who has frequently been used in midfield by the manager.

Leaving Stamford Bridge on deadline day is midfielder Gael Kakuta, who has moved on loan to Lazio for the rest of the season.

Once tipped as a future star after outshining the likes of Clement Grenier, Alexandre Lacazette and Antoine Griezmann in France's junior sides, Kakuta, 22, has faded after a series of underwhelming loan moves while his former teammates have taken centre stage.

"It's a huge waste, because I've already said it and I'll repeat it: he was the most talented one of his generation," French scout Guy Hillion told L'Equipe earlier this week of Kakuta, who recently decided to end his loan deal at Vitesse Arnhem early and was training with Chelsea's reserve team.

"He could be exceptional. But talent is not enough. There comes a time, when you accumulate failures, that there are problems at every club you go to, you have to ask yourself the right questions and question yourself. Because before Arnhem, there was Bolton, Fulham and Dijon."